Update TopViewOfBTUsingDFS.java

Author: harshithasudhakar

Binary Tree/TopViewOfBTUsingDFS.java

@@ -26,26 +26,28 @@ static void buildTree(int[] nodes){
         q.add(root);
         int i = 1;
 
-        while(!q.isEmpty()){
+        while(!q.isEmpty() && i<nodes.length){
             Node current = q.poll();
-            if(i<nodes.length && nodes[i] != -1){
+            if(nodes[i] != -1){
                 if(current.left == null){
-                    current.left = new Node(nodes[i++]);
+                    current.left = new Node(nodes[i]);
                     q.add(current.left);
                 }
             }
+            i++;
 
-            if(i<nodes.length && nodes[i] != -1){
+            if(nodes[i] != -1){
                 if(current.right == null){
-                    current.right = new Node(nodes[i++]);
+                    current.right = new Node(nodes[i]);
                     q.add(current.right);
                 }
             }
+            i++;
         }
     }
 
     static void topview(Node root){
-        Map<Integer, int[]> map = new TreeMap<>(); //{hd: [node.val, level]}
+        Map<Integer, int[]> map = new TreeMap<>();
         dfs(root, map, 0, 0);
         System.out.print("Top view: ");
         for(int[] pairs : map.values()){